Valve-gear of steam-engines



UNITED STATES PATENT OFFICE.

SAMUEL SVVARTZ, 0F BUFFALO, NEIV YORK.

VALVE-GEAR OF STEAMENGINES.

Specification of Letters Patent No. 17,585, dated June 16, 1857.

To all whom it may concern:

Be it known that I, SAMUEL Swiin'rz, of the city of Buffalo, in the county of Erie and State of New York, have invented certain' new and useful Improvements in the Construction and Arrangement of Valve- Gear for Steam-Engines; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings and the letters of reference marked thereon.

The nature of my invention consists, first, in placing a tappeti, or valve lifter, upon a wheel or segment, and giving said wheel or segment a rotary motion, in combination with an alternating sliding or reciprocating motion; second, in arresting the reciprocating motion of the said wheel 0r segment, and commencing its rotary motion at a point where its rotary motion will cause the tappet to strike the valve toe on a line (or nearly so) drawn through the center of the joint and perpendicular to the line of reciprocatlng motion.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

Figure I, is a front elevation. Fig. II is a transverse section; Fig. III, plan of spring clutches and stops; Fig. IV, arm of rock shaft and its connection to valve gear.

Explanation of Fig. l: a, tappet or valve lifter. This is placed on the segment or wheel B. B, wheel, or segment. This is connected by an arbor or axis to the cross head (c) and has a sliding motion with the cross head and also an alternating rotary motion. C, cross head. I), slide on which cross head moves. e, spring, which operates the clutch (f) to arrest the rotary motion of the wheel (B) at the proper point.`

There are notches cut in the rim of the wheel (B) into which the spring forces the clutches. These notches are shown at .1?. f. clutch, which is moved by spring (c). g, stops. This 1s a pin or bar projecting from the slide The object of this stop is to arrest the movementI of the sliding head, and at the same time unclntch the wheel so as to allow the wheel to commence its rotary motion at the proper point, to cause the tappet` to strike the valve toe on the center line of its point. lli, axis, of segment or wheel (B) by which it is connected to the cross head. The tappet is placed on the wheel (B). I, valve stem. L, valve toe, or lifter. V, joint of valve toe. m., guard, or heel extension of valve toe. Its object is to guard against accident in case either spring should break or fail to act. Y, line, drawn through the center of the joint (V) and perpendicular to the line of reciprocating motion. V2, line of reciprocating motion. n, rod, which forms a connection between the valve toe, and the thimble on thc sleeve of valve lstem. This rod is jointed at its connection with the valve toe and thimble. P, thimble which slides up and down on sleeve (of valve stem) and t0 which the rod n is jointed. r, sleeve, which slides over the valve stem. S, hand Wheel or set screw for the purpose of making the thimblc I) tast 'to the valve stem 0r sleeve at any point desired.V The thimble is raised and lowered on the sleeve by which means the position of the valve toe is changed (from its joint outward) and thereby the steam may be cnt off at any point in the stroke desired. The valve toe is stationary at its point of connection with the sleeve, or valve stem, but its angle from its joint outward may be altered at pleasure by raising or lowering the thimble P on the sleeve or valve stem as aforesaid. )Vlien lowered the connection ofthe tappet` with it is prolonged. lVllcn raised, it is shortened. The valve is raised and steam admitted into the cylinder the moment the tappct strikes the valve toe. The valve is held up, as long as the contact between the tappet and valve toe is continued. The moment this contact is broken, the valve drops and the steam is cnt oil". Consequently the steam can be cut olf at any desired point in the stroke, by raising or lmvering the thimble and this can bc donc without any change of gear and while the engine is in full motion. The point ot' contact between the tappet and valve toe is precisely when the wheel commences its axial motion, and is the same under all circumstances; but the point where the contact is broken, and the steam cut off,

may be varied and adjusted, as desired in the manner already described. T, puppet head to steady the valve stem.

Explanation of Fig. II: Letters of the same kind refer to like parts as in Fig. I, and already described: l standard or support for the puppet heads.

Explanation of Fig. III: e, is the spring which forces the clutch f into the notch :c in Wheel B at the proper time. f is the clutch. g2, projection of clutch which comes in contact With the stop (g) by which the clutch is moved out of the notch in the rim of the Wheel, and the wheel allowed to take its rotary motion. The clutch strikes the stop before the cross head comes to the limit of its reciprocating motion, so as to stop the movement of the clutch While the cross head and Wheel pass on until the wheel is unclutched and ready to take its rotary motion. This is the same in respect to either clutch and the movement of the wheel in either direction.

Explanation of Fig. IV: M, rock shaft. J, arm of rock shaft. K, connecting rod, forming a connection between the rock shaft and Wheel B. This rock shaft (through its connecting rod K) gives both the reciprocating and rotary motion to the Wheel B the said reciprocating and rotary motion just equaling the distance made by the arm J. K2, connecting rod, from rock shaft arm to duplicate valve gear. This duplicate, is not shown in the drawing, but is in all respects similar to that which is herein described, both in construction and operation, and Works the valve in the opposite end of the cylinder.

Operation: Now let it be supposed that the rock shaft arm is the proximate power, Which Works the valve gear. Let it also be supposed that the tappet Wheel is connected to the arm of the rock shaft by means of a connecting rod. The engine is on the center or end of stroke and ready to take steam, the arm of the rock shaft stands perpendicular to the line of sliding motion of the cross head, the cross head at farther end of slide (from rock shaft arm), the tappet wheel just unclutched, and ready to commence its rotary motion and the tappet under the center of the joint of the valve toe as represented in Fig. I. The movement noW commences. The motion of the arm of the rock shaft is now toward the tappet Wheel, and produces the rotary motion of the Wheel; which rotary motion causes the tappet to strike the valve toe under the center of its joint and raises the valve. The valve toe continues to rest on the tappet, holding the valve open, until the rotary motion o the Wheel carries the tappet beyond the point of contact with the valve toe, at which point the valve closes and the steam is cut olf.

The rotation, or rotary motion of the Wheel is arrested at the time the arm of the rock shaft has reached its limit, at which time the other spring clutch drops into a notch in the rim of the wheel and prevents the rotary motion of the wheel While the arm travels to its perpendicular position. The arm immediately commences its return movement, and (simultaneously therewith), causes the return sliding movement of the cross head and tappet Wheel. This return sliding movement (of the cross head and tappet Wheel) will continue until the arm has reached its perpendicular position and the cross head its opposite limit on the slide and the tappet wheel again unclutched and ready to take its rotary motion in the opposite direction to that already described. At this point the engine has made half stroke and the tappet has slightly passed the center line of the joint so that the valve Will not be raised when the tappet Wheel moves in this direction. The arm passes on with the Wheel in its reverse rotary motion, until both reach their limit in this direction. T lien the arm immediately returns to its perpendicular position thereby producing the return sliding movement of the cross head and tappet Wheel and bringing all the parts to pre eisely the same position Where the movement commenced, the engine having now eompleted its full stroke.

It should be borne in mind that the valve gear and its motions already described has its duplicate or mate, which Works the valve in the opposite end of the cylinder and by which the motion of the engine in the last half of its stroke above described is completed. This mate or duplicate valve gear is connected to the arm of the rock shaft by means of the connecting rod I'Z, Fig. IV.

The description already given will apply equally Well to the duplicate, it being understood that the construction and operation of the two are precisely alike, but being mated each acts upon its valve in point of time opposite to the other.

In order to vary the cut off to any point of the stroke I raise or depress the tliinible on the sleeve of the valve stem and by so doing elevate or depress the outer end of the valve toe, and thereby vary the point Where the tappet leaves the valve toe, consequently the steam may be cut ofi' at any desired point in the stroke, or at full stroke.

Then you wish to reverse the motion of the engine it is only necessary to unhook or disengage the valve motion from the engine, and give the valve gear a half stroke movement the forward Way with the starting bar, and then connect With the engine or Work the valves by hand.

I claim- 1. The tappet, or valve lifter, upon a Wheel or segment, and giving said Wheel` or drawn through the center of the joint and 10 segment a rotary motion, 1n coinbinatlon perpendicular to the line of reciprocating with a reciprocating motion for the purposes motion for the purposes and substantially as and substantially as herein set forth. herein described.

2. I claim arresting the reciprocatind moy f tion of the said Wheel or segment, andbcoin- SAML SVART/J' mencing its rotary motion at a point Where iYitnesses: its rotary motion will cause the tappet` to E. B. FoRBUsI-I,

strike the valve toe, on a line (or nearly so) M. W. BROWN. 

